scholarly journals IL-Y Aggravates Murine Chronic Graft-Versus-Host Disease by Enhancing T and B Cell Responses

2020 ◽  
Vol 11 ◽  
Author(s):  
Li Wan ◽  
Ziqi Jin ◽  
Bo Hu ◽  
Kangkang Lv ◽  
Lei Lei ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Treg Cells ◽  
Host Disease ◽  
Mhc Ii ◽  
Follicular Helper ◽  
Tnf Α ◽  
Dsdna Antibody ◽  
Il Y A

IL-Y, a synthetic member of IL-12 cytokine family, was found to exert potent immunosuppressive effects by inhibiting the differentiation and activation of Th1 and Th17 cells. However, the role of IL-Y in the development of chronic graft-versus-host disease (cGVHD) remains unknown. Here, using murine models of scleroderma-like and lupus-like cGVHD, we examined the function of IL-Y in the pathogenesis of cGVHD by hydrodynamically injecting minicircle-IL-Y expressing plasmids (MC IL-Y). In contrast with the reported immune suppressive function of IL-Y, administration of MC IL-Y enhanced cGVHD severity reflected by deteriorated multi-organ pathologic damages. In lupus-like cGVHD model, urine protein and the serum anti-dsDNA antibody (IgG) were significantly upregulated by IL-Y treatment. Further study demonstrated that IL-Y impacts both donor T and B cell response. In T cells, IL-Y inhibited the generation of CD4+Foxp3+ regulator T (Treg) cells during the development of cGVHD. IL-Y may also increase the infiltration of pathogenic TNF-α producing CD4+ and CD8+ T cells through IL-27Rα in recipient spleens, as this effect was diminished in IL-27Rα deficient T cells. Moreover, IL-Y enhanced the differentiation of ICOS+ T follicular helper (Tfh) cells. In B cells, the percentage of germinal center (GC) B cells in recipient spleens was significantly upregulated by MC IL-Y plasmid administration. The levels of co-stimulatory molecules, MHC-II and CD86, on B cells were also enhanced by IL-Y expression. Taken together, our data indicated that IL-Y promoted the process of cGVHD by activating pathogenic T and B cells.

scholarly journals CD10 delineates a subset of human IL-4 producing follicular helper T cells involved in the survival of follicular lymphoma B cells

Blood ◽  
2015 ◽  
Vol 125 (15) ◽  
pp. 2381-2385 ◽  
Author(s):  
Patricia Amé-Thomas ◽  
Sylvia Hoeller ◽  
Catherine Artchounin ◽  
Jan Misiak ◽  
Mounia Sabrina Braza ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Follicular Lymphoma ◽  
B Cell ◽  
Germinal Center ◽  
Helper T Cells ◽  
Follicular Helper T Cells ◽  
Follicular Helper ◽  
Key Points ◽  
Cell Niche

Key Points CD10 identifies a unique subset of fully functional germinal center TFH that are activated and amplified within the FL cell niche. FL CD10pos TFH specifically display an IL-4hiIFN-γlo cytokine profile and encompass the malignant B-cell-supportive TFH subset.

Malignant B Cells Skew the Balance between Treg Cell and TH17 Cell Differentiation in B-Cell Non-Hodgkin Lymphoma (NHL).

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1347-1347
Author(s):  
Zhi-Zhang Yang ◽  
Anne J. Novak ◽  
Thomas E. Witzig ◽  
Stephen M. Ansell
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Th17 Cell ◽  
Th17 Cells ◽  
Foxp3 Expression ◽  
Treg Cells ◽  
Th17 Cell Differentiation

Abstract Numerous clinical therapies have attempted to modulate tumor cell immunity, but for the most part, have proven unsuccessful. The inability to produce or augment an effective immune response is due in part to regulatory T (Treg) cells, which inhibit CD4 and CD8 T cell function. Our group has recently shown that Treg cell numbers are elevated in NHL tumors and that NHL B cells induce the development of Treg cells thereby inhibiting anti-tumor responses. The ability of NHL B cells to direct the cellular composition of their microenvironment is critical to our understanding of tumor immunity and we therefore wanted to determine if NHL B cells also directed the expansion or reduction of other T cell populations. IL-17-secreting CD4+ T cells (TH17), a newly characterized CD4+ T helper cell lineage, promote inflammation and play an important role in autoimmune disease. IL-17 has been shown to inhibit tumor cell growth suggesting a potential role for TH17 cells in anti-tumor immunity. We therefore set out to determine if TH17 cells were present in NHL tumors and whether or not their numbers were regulated by NHL B cells. Using unsorted mononuclear cells from malignant lymph nodes, we were unable to detect IL-17 expression in resting CD4+ T cells or CD4+ T cells activated with PMA/Ionomycin stimulation (less than 1%). However, IL-17-secreting CD4+ T cells could be detected in significant numbers in inflammatory tonsil and normal PBMCs. Interestingly, depletion of CD19+ NHL B cells from mononuclear cells obtained from patient biopsies resulted in detection of a clear population of IL-17-secreting CD4+ T cells (5%). These results suggest that NHL B cells suppress TH17 cell differentiation. The frequency of IL-17-secreting CD4+ T cells could not be further enhanced by the addition of exogenous TGF-b and IL-6, a cytokine combination favoring for TH17 differentiation, suggesting a further impairment of TH17 cell differentiation in the tumor microenvironment. In contrast, Foxp3 expression could be detected in resting CD4+ T cells (30%) and could be induced in CD4+CD25−Foxp3− T cells activated with TCR stimulation (28%). Contrary to the inhibition of TGF-b-mediated TH17 differentiation, Foxp3 expression could be dramatically upregulated by TGF-b in intratumoral CD4+ T cells (35%). In addition, lymphoma B cells strongly enhanced Foxp3 expression in intratumoral CD4+CD25−Foxp3−. Furthermore, when added together, the frequency of Foxp3+ T cells and Foxp3-inducible cells reached up to 60% of CD4+ T cells in tumor microenvironment of B-cell NHL. These findings suggest that the balance of effector TH17 cells and inhibitory Treg cells is disrupted in B-cell NHL and significantly favors the development of inhibitory Treg cells. Our data indicate that lymphoma B cells are key factor in regulating differentiation of intratumoral CD4+ T cells toward inhibitory CD4+ T cells.

Phase II Clinical Trial of Denileukin Diftitox In Combination with Rituximab In Previously Untreated Follicular B-Cell Non-Hodgkin's Lymphoma

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2862-2862
Author(s):  
Stephen M Ansell ◽  
Hui Tang ◽  
Grzegorz S. Nowakowski ◽  
Daniel Nikcevich ◽  
Garth D Nelson ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Adverse Events ◽  
Follicular Lymphoma ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Treg Cells ◽  
Time To Progression ◽  
Denileukin Diftitox

Abstract Abstract 2862 Follicular lymphoma (FL) is a B-cell malignancy that exhibits significant intratumoral infiltration by non-malignant T lymphocytes. The pathophysiological significance of infiltrating T cells is poorly understood but recent studies have suggested that CD4+CD25+ regulatory T (Treg) cells are highly represented in lymph nodes involved by FL. These Treg cells display the ability to suppress the proliferation and cytokine production of other tumor-infiltrating T cells and migrate to areas of B-cell lymphoma in response to chemotactic signals provided by the malignant B-cells. Denileukin diftitox, a chimeric immunotoxin composed of the modified cytotoxic domain of diphtheria toxin and human interleukin-2 (IL-2) protein, targets cells expressing CD25 and has proven efficacy in patients with relapsed B-cell lymphoma. In this study, we combined denileukin diftitox with rituximab in a cohort of previously untreated, advanced-stage follicular lymphoma patients. Our hypothesis was that denileukin diftitox would deplete the Treg cells, thereby removing the inhibition of the immune response, and rituximab would deplete the B-cells thereby preventing further recruitment of Treg cells to the areas of lymphoma. Between August 2008 and March 2010, twenty-four patients with stage III and IV follicular grade 1 or 2 non-Hodgkin lymphoma were accrued to the study. One patient died before treatment was given and is not included in the analysis. The median age was 60 years (range: 27 – 79), 12 (52%) of the patients were male, 19 (83%) had a PS of 0 and 4 (17%) had a PS of 1. Based on the Follicular Lymphoma International Prognostic Index (FLIPI), 3 (13%) were low risk, 14 (61%) were intermediate risk and 6 (26%) were high risk. Patients received rituximab 375 mg/m2 on days 1, 8, 15 and 22 and denileukin diftitox 18 mcg/kg/day on days 1–5 every 3 weeks for 4 cycles. A median of 4 cycles of therapy was given (range: 1 – 4). Thirteen patients completed treatment per protocol (57%), however 5 patients discontinued treatment due to adverse events (22%), 2 refused further treatment (9%) and 1 discontinued due to disease progression (4%). Nine of the 23 patients (39%; 95% CI: 21–61%) responded to treatment, 3 (13%) had a complete response and 6 (26%) had a partial response. Twenty-one patients (91%) are alive with a median follow-up of 8.7 months (range: 3.4–19.5). Seven (30%) patients have progressed and two (8.7%) has died. The median time to progression is 13.4 months (95% CI: 10.4 – NA). The combination, however, was associated with significant toxicity. Thirteen patients (57%) experienced grade 3 or greater adverse events. Six patients (26%) had symptoms of capillary leak syndrome, 1 of whom died. In correlative studies performed on the peripheral blood, the number of CD25+ T-cells decreased after treatment when compared to pretreatment numbers (median 24%; range: 8–44%). We conclude that while the addition of denileukin diftitox to rituximab decreased the numbers of CD25+ T-cells, denileukin diftitox contributed significantly to the toxicity of the combination. Furthermore, the overall response rate and time to progression in this study were no better than what would be expected in follicular lymphoma patients treated with rituximab alone. Disclosures: No relevant conflicts of interest to declare.

The shifted balance between circulating follicular regulatory T cells and follicular helper T cells in patients with ulcerative colitis

2017 ◽  
Vol 131 (24) ◽  
pp. 2933-2945 ◽  
Author(s):  
Xinrui Wang ◽  
Yonggang Zhu ◽  
Manli Zhang ◽  
Jie Hou ◽  
Hongjuan Wang ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
T Cells ◽  
B Cell ◽  
Mayo Clinic ◽  
Treg Cells ◽  
Tfh Cells ◽  
Follicular Helper ◽  
Immune Balance ◽  
Cell Immunity ◽  
B Cell Immunity

B-cell immunity participates in the pathogenesis of ulcerative colitis (UC). The immune balance between follicular regulatory T (TFR) cells and follicular helper T (TFH) cells is important in regulating B-cell responses. However, the alteration of TFR/TFH balance in UC remains unclear. Peripheral blood from 25 UC patients and 15 healthy controls was examined for the frequencies of circulating TFR, TFH, and regulatory T (Treg) cells by flow cytometry. Levels of serum cytokines were measured using cytometric bead array (CBA). Disease activity was evaluated by the Mayo Clinic Score. Compared with controls, UC patients exhibited significant reductions in circulating Foxp3+CXCR5+ TFR cells, the subset interleukin (IL)-10+Foxp3+CXCR5+ cells, and Treg cells, but significant expansions in Foxp3−CXCR5+ TFH cells and IL-21+Foxp3−CXCR5+ cells. UC patients also had reduced levels of serum IL-10 and elevated levels of serum IL-21. The values of Mayo Clinic Score, C-reactive protein (CRP), or erythrocyte sedimentation rate (ESR) in UC patients were negatively correlated with circulating TFR cells, serum IL-10 level, and TFR/TFH ratio, while positively correlated with circulating TFH cells and serum IL-21 level. Alterations in circulating TFR and TFH cells shift the balance from immune tolerance to immune responsive state, contributing to dysregulated B-cell immunity and the pathogenesis of UC.

scholarly journals CXCR5+PD-1+ follicular helper CD8 T cells control B cell tolerance

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuhong Chen ◽  
Mei Yu ◽  
Yongwei Zheng ◽  
Guoping Fu ◽  
Gang Xin ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Cd8 T Cells ◽  
T Cell Subsets ◽  
Cell Tolerance ◽  
B Cell Tolerance ◽  
Autoantibody Production ◽  
Tfh Cells ◽  
Follicular Helper

Abstract Many autoimmune diseases are characterized by the production of autoantibodies. The current view is that CD4+ T follicular helper (Tfh) cells are the main subset regulating autoreactive B cells. Here we report a CXCR5+PD1+ Tfh subset of CD8+ T cells whose development and function are negatively modulated by Stat5. These CD8+ Tfh cells regulate the germinal center B cell response and control autoantibody production, as deficiency of Stat5 in CD8 T cells leads to an increase of CD8+ Tfh cells, resulting in the breakdown of B cell tolerance and concomitant autoantibody production. CD8+ Tfh cells share similar gene signatures with CD4+ Tfh, and require CD40L/CD40 and TCR/MHCI interactions to deliver help to B cells. Our study thus highlights the diversity of follicular T cell subsets that contribute to the breakdown of B-cell tolerance.

Malignant B Cell-Derived TGF-β Controls the Generation of TH1, TH17 and Treg Cells in the Tumor Microenvironment of B-Cell Non-Hodgkin Lymphoma (NHL).

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1551-1551
Author(s):  
Zhi-Zhang Yang ◽  
Anne Novak ◽  
Thomas E. Witzig ◽  
Stephen M. Ansell
Keyword(s):  
T Cells ◽  
B Cells ◽  
Tumor Microenvironment ◽  
B Cell ◽  
Cd4 T Cells ◽  
Th17 Cell ◽  
Treg Cells ◽  
Cell Generation ◽  
Human B Cell

Abstract Background: Our previous work has shown that malignant B cells induce the development of intratumoral Treg cells that inhibit the host anti-tumor response. In contrast to an increase in Treg cells, we found that the number of effector T helper cells (TH1, TH2 and TH17) was low in B-cell NHL tumors, suggesting an imbalance between Treg and TH cells in the tumor microenvironment. Understanding the mechanism(s) of this imbalance is important to the development of treatments to enhance host immunity and in previous work we have shown that signaling through CD70, CD80 and CD86 plays a role. Since soluble factors, particularly TGF-β, have an important role in directing T-cell differentiation, we evaluated in this study the role of TGF-β in the lymphoma microenvironment. Goal: To determine the effect of TGF-β on the generation of intratumoral TH1, TH17 and Treg cells in human B-cell NHL. Results: Human B-cell NHL specimens were obtained from consenting patients and were used for all experiments. Using an ELISA assay, we found that malignant B cells variably secrete TGF-β - median 100 pg/ml per million cells (range: undetectable −229 pg/ml, n=7). Using flow cytometry, we showed that addition of exogenous TGF-β enhanced the expression of Foxp3+ in activated CD4+ or CD4+CD45RA+ or CD4+CD45RO+ nodal T cells, suggesting that TGF-β promotes the generation of Treg cells in tumor microenvironment. In contrast, TGF-β suppressed expression of IFN-g in activated CD4+ T cells and inhibited the up-regulation of IL-12 and IL-23-induced IFN-γ expression in CD4+ cells, indicating that TGF-β suppresses the generation of TH1 cells. TGF-β alone slightly inhibited IL-17 expression in CD4+ T cells; however, TGF-β, in the presence of IL-6 and IL-23, upregulated IL-17 expression in CD4+ T cells, suggesting proinflammatory cytokines are able to reverse the suppression induced by TGF-β. These results indicate that TGF-β plays an important role in the regulation of intratumoral TH17 cell generation. In additional experiments, TGF-β was found to exert a suppressive effect on the proliferation of both CD4+ and CD8+ intratumoral T cells. However, treatment with TGF-β enhanced IL-2 production by intratumoral CD4+ T cells detected by intracellular staining of flow cytometry. Interruption of IL-2 signaling by anti-IL-2 Ab abolished the upregulation of TGF-β-mediated Foxp3 expression and enhanced the production of IL-17 in CD4+ T cells. Furthermore, treatment with anti-IL-2 Ab reversed the inhibition of NHL B cell-mediated TH17 cell generation. Conclusion: These results suggest that TGF-β controls the generation of TH1, TH17 and Treg cells contributing to the imbalance of effector TH cells and inhibitory Treg cells in the tumor microenvironment of B-cell NHL through IL-2. Since malignant B-cells produce TGF-β, these results further support the important role of malignant B cells in the regulation of intratumoral T cell generation and the host immune response.

Efficient Treatment of Murine Acute Graft-Versus-Host Disease with In Vitro Expanded CD4+CD25+ Regulatory T Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2987-2987
Author(s):  
Tina J Boeld ◽  
Kristina Doser ◽  
Corinna Lang-Schwarz ◽  
Elisabeth Huber ◽  
Reinhard Andreesen ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Regulatory T Cells ◽  
Graft Versus Host Disease ◽  
Acute Gvhd ◽  
Treg Cells ◽  
Host Disease ◽  
Graft Versus Host ◽  
Acute Graft

Abstract Abstract 2987 Acute graft-versus-host disease (GVHD) is a frequent complication after allogeneic bone marrow transplantation (BMT). We previously showed that the adoptive transfer of donor-type CD4+CD25+ regulatory T cells (Treg) at the time of BMT prevents acute GVHD in murine models. However, the therapeutic potential of donor-derived Treg cells for the treatment of established acute GVHD has not yet been examined in detail. In analogy to potential clinical applications we now tested the capacity of in vitro expanded Treg cells to ameliorate acute GVHD after haploidentical BMT (BALB/c→CB6F1). CD4+CD25highCD62L+ Treg cells were purified by FACS and stimulated polyclonally using anti-CD3/CD28-coated beads. Cells expanded on average 130±19-fold (n=7) within 2 wks and maintained high levels of FoxP3 expression (96, 8±0, 8% FoxP3+ cells; n=7) as well as potent immunosuppressive activity in vitro. For the induction of acute GVHD CB6F1 recipients were lethally irradiated and transplanted with 2.5×106 BM cells in combination with 5×106 splenocytes. All animals developed severe GVHD by d11, as revealed by an increase of the GVHD severity score (2.3±0.4 in GVHD animals vs 0±0 in BM controls, p<0.001, n=1–11) and by histological analyses of the gut (score: 7.8±0.4 for the GVHD group vs 0.2±0.2 for BM controls, p =0.046, n=3). When animals with acute GVHD were treated with 5×106 expanded CD4+CD25highCD62L+ Treg cells on d11 after BMT, they initially developed progressive GVHD comparable to non-treated GVHD animals, as indicated by weight loss and an increase of the GVHD score. However from d44 post BMT onwards, Treg-treated GVHD animals regained body weight (d44: 75±3% vs 67±2% of initial weight; p <0.05; n=9–10) and their clinical GVHD score (d44: 6±0 vs 4.3±0.4; p <0.05; n=9–10) decreased. While all non-treated GVHD animals succumbed to disease by d67 after transplantation, 50% of Treg-treated GVHD animals survived for at least 100d (p =0, 002; n=16–21). As immune reconstitution and in particular reconstitution of the lymphocyte compartment is impaired in animals with GVHD, we analyzed the effect of Treg therapy on the reconstitution of the lymphoid and myeloid compartment. At d21 after BMT spleen and BM of non-treated as well as Treg-treated GVHD animals were completely lymphopenic as compared to control mice and both organs contained exceptionally high numbers of granulocytes. Unlike non-treated GVHD animals, however, Treg-treated recipients by d60 showed a recovery of the lymphocyte compartment in spleen (10±2.6×106 T cells and 23.5±12.5×106 B cells in Treg-treated vs 3.0±0.6×106 T cells and 1.5±0.4×106 B cells in non-treated GVHD animals vs 26.25±2.6×106 T cells and 63.9±9.1×106 B cells in BM controls) and BM (0.7±0.1×106 T cells and 8.6±4×106 B cells in Treg-treated vs 0.3±0.01×106 T cells and 0.7±0.4 ×106 B cells in non-treated GVHD animals vs 0.4±0.03×106 T cells and 11.2±0.6×106 B cells in BM controls), while the number of granulocytes decreased constantly. Successful treatment with Treg cells was finally accompanied by a reconstitution of the lymphatic system comparable to control mice. Furthermore, successfully treated mice showed only mild histological signs of gut GVHD at d100 that was significantly lower then those in non-treated GVHD animals with end-stage disease (score: 4.2±1 vs 9.9±1.5 in treated vs non-treated animals, p =0.006, n=4–6). Taken together, these results indicate that in vitro expanded natural Treg cells may not only be effective for the prevention, but also for the treatment of acute GVHD after allogeneic BMT. Disclosures: No relevant conflicts of interest to declare.

scholarly journals B cell priming for extrafollicular antibody responses requires Bcl-6 expression by T cells

2011 ◽  
Vol 208 (7) ◽  
pp. 1377-1388 ◽  
Author(s):  
Sau K. Lee ◽  
Robert J. Rigby ◽  
Dimitra Zotos ◽  
Louis M. Tsai ◽  
Shimpei Kawamoto ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Antibody Responses ◽  
B Cell Differentiation ◽  
Tfh Cells ◽  
Follicular Helper ◽  
Microbial Infections

T follicular helper cells (Tfh cells) localize to follicles where they provide growth and selection signals to mutated germinal center (GC) B cells, thus promoting their differentiation into high affinity long-lived plasma cells and memory B cells. T-dependent B cell differentiation also occurs extrafollicularly, giving rise to unmutated plasma cells that are important for early protection against microbial infections. Bcl-6 expression in T cells has been shown to be essential for the formation of Tfh cells and GC B cells, but little is known about its requirement in physiological extrafollicular antibody responses. We use several mouse models in which extrafollicular plasma cells can be unequivocally distinguished from those of GC origin, combined with antigen-specific T and B cells, to show that the absence of T cell–expressed Bcl-6 significantly reduces T-dependent extrafollicular antibody responses. Bcl-6+ T cells appear at the T–B border soon after T cell priming and before GC formation, and these cells express low amounts of PD-1. Their appearance precedes that of Bcl-6+ PD-1hi T cells, which are found within the GC. IL-21 acts early to promote both follicular and extrafollicular antibody responses. In conclusion, Bcl-6+ T cells are necessary at B cell priming to form extrafollicular antibody responses, and these pre-GC Tfh cells can be distinguished phenotypically from GC Tfh cells.

scholarly journals IL-21 regulates germinal center B cell differentiation and proliferation through a B cell–intrinsic mechanism

2010 ◽  
Vol 207 (2) ◽  
pp. 365-378 ◽  
Author(s):  
Dimitra Zotos ◽  
Jonathan M. Coquet ◽  
Yang Zhang ◽  
Amanda Light ◽  
Kathy D'Costa ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Affinity Maturation ◽  
Memory B Cells ◽  
Target Cells ◽  
B Cell Differentiation ◽  
Follicular Helper

Germinal centers (GCs) are sites of B cell proliferation, somatic hypermutation, and selection of variants with improved affinity for antigen. Long-lived memory B cells and plasma cells are also generated in GCs, although how B cell differentiation in GCs is regulated is unclear. IL-21, secreted by T follicular helper cells, is important for adaptive immune responses, although there are conflicting reports on its target cells and mode of action in vivo. We show that the absence of IL-21 signaling profoundly affects the B cell response to protein antigen, reducing splenic and bone marrow plasma cell formation and GC persistence and function, influencing their proliferation, transition into memory B cells, and affinity maturation. Using bone marrow chimeras, we show that these activities are primarily a result of CD3-expressing cells producing IL-21 that acts directly on B cells. Molecularly, IL-21 maintains expression of Bcl-6 in GC B cells. The absence of IL-21 or IL-21 receptor does not abrogate the appearance of T cells in GCs or the appearance of CD4 T cells with a follicular helper phenotype. IL-21 thus controls fate choices of GC B cells directly.

scholarly journals An Early CD4+ T Cell–dependent Immunoglobulin A Response to Influenza Infection in the Absence of Key Cognate T–B Interactions

2003 ◽  
Vol 198 (7) ◽  
pp. 1011-1021 ◽  
Author(s):  
Mark Y. Sangster ◽  
Janice M. Riberdy ◽  
Maricela Gonzalez ◽  
David J. Topham ◽  
Nicole Baumgarth ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Mhc Ii ◽  
Cell Responses ◽  
Iga Response ◽  
B Cell Responses

Contact-mediated interactions between CD4+ T cells and B cells are considered crucial for T cell–dependent B cell responses. To investigate the ability of activated CD4+ T cells to drive in vivo B cell responses in the absence of key cognate T–B interactions, we constructed radiation bone marrow chimeras in which CD4+ T cells would be activated by wild-type (WT) dendritic cells, but would interact with B cells that lacked expression of either major histocompatibility complex class II (MHC II) or CD40. B cell responses were assessed after influenza virus infection of the respiratory tract, which elicits a vigorous, CD4+ T cell–dependent antibody response in WT mice. The influenza-specific antibody response was strongly reduced in MHC II knockout and CD40 knockout mice. MHC II–deficient and CD40-deficient B cells in the chimera environment also produced little virus-specific immunoglobulin (Ig)M and IgG, but generated a strong virus-specific IgA response with virus-neutralizing activity. The IgA response was entirely influenza specific, in contrast to the IgG2a response, which had a substantial nonvirus-specific component. Our study demonstrates a CD4+ T cell–dependent, antiviral IgA response that is generated in the absence of B cell signaling via MHC II or CD40, and is restricted exclusively to virus-specific B cells.

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